Method and device for sensing a position of an object

ABSTRACT

A sensing method and device for sensing the position of an object are provided. The sensing device comprises a light source for generating a plane light, and a sensor unit disposed at one side of the light source. The sensing method comprises driving the light source to generate the plane light, forming a reflective light distribution by the object reflecting the plane light; and estimating a relative distance between the object and the light source according to the reflective light distribution.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims priority under 35 U.S.C. §119(a)on Patent Application No(s). 100116225 filed in Taiwan, R.O.C. on May 9,2011, the entire contents of which are hereby incorporated by reference.

BACKGROUND

1. Technical Field

The disclosure relates to a sensing method and device, and moreparticularly to a sensing method and device for sensing the position ofan object.

2. Related Art

The touch devices can be classified to be resistance touch device,capacitance touch device, optical touch device, and etc according todifferent working principles. The merits of the optical touch device arecomfortable touch feeling, low material cost, and so on.

Optical touch device has light source and sensor unit disposed at thesurrounding of the touch panel or at the bottom of the device. Theoptical touch device operates based on the light interruption principle.That is, when the light emitted from a light source is interrupted, itmeans that a user is performing a touch operation, and as a result thelight cannot go ahead along the original emitting direction. A sensorunit senses the light interruption and transmits a sensed signalcorresponding to the light interruption to a processing unit todetermine the position of the touch point.

FIG. 1 shows an optical touch device according to the related art. Thetouch device 10 comprises a base plate 101, a first image sensing module103 disposed at the upper left corner of the base plate 101, a secondimage sensing module 104 disposed at the upper right corner of the baseplate 101, a processing circuit 106 having signal connections with thefirst image sensing module 103 and the second image sensing module 104,and a reflection element 102 disposed at the surrounding of the baseplate 101. The first and second image sensing modules are used tocapture images in the touch area 107. The processing circuit 106 is usedto calculate the position of an object 11 in the touch area 107according to the captured images.

In FIG. 1, infrared ray is emitted from the image sensor modules to theobject 11. The object 11 reflects the infrared ray and generates animage for determining the position of the object 11. The image receivedby the image sensor modules can be divided into two parts. One is thezone with higher brightness which is reflected by the reflection element102, and the other is the dark zone because of the light interruption bythe object 11.

In other words, the touch device 10 according to the related art usesthe bright zone and the dark zone to provide the touch area 107, whichis the area formed on the base plate 101 by the reflection element 102.In this case, when a user performs a touch operation by using the object11 (finger or touch pen), the touch area 107 is limited in the areaformed by the reflection element 102.

Because the touch device 10 according to the related art uses the brightzone generated by the reflection element 102 as references fordetermining the position of the object to be detected, the touch device10 has the following shortcomings.

Firstly, the touch device is not easily to be carried with due to thesize of the base plate 101 and the reflection element 102. The usageenvironment of the touch area is limited by the real size of the baseplate 101 and the reflection element 102. Secondly, the cost of the baseplate 101 and the reflection element 102 which adds additional cost ofthe touch device cannot be ignored. That is, the manufacture and usageof a portable electronic device comprising the related art touch devicehave a great limitation.

Furthermore, according to the above mentioned working principle of theoptical touch device 10, reflection element 102 made of retro-reflectivematerial must be used in the optical touch device 10, and therefore themanufacture cost of the optical touch device and the size of thereflection area of the optical touch device 10 according to the relatedart are limited.

SUMMARY

In one aspect, a method for sensing a position of an object isdisclosed. The method comprises driving a light source to generate aplane light, reflecting the plane light by the object to form areflective light distribution, and estimating a relative distancebetween the object and the light source according to the reflectivelight distribution.

In another aspect, a device for sensing a position of an object isdisclosed. The device comprises a light source for generating a planelight and a first sensor unit disposed at one side of the light sourcefor estimating a relative distance between the object and the lightsource according to a reflective light distribution. The reflectivelight distribution is formed by the object reflecting the plane light.

In yet another aspect, a device for sensing a position of an object isdisclosed. The device comprises a light source for generating a planelight and a sensor unit disposed at one side of the light source forestimating a relative distance between the object and the light sourceaccording to a reflective light distribution. The reflective lightdistribution is formed by the object reflecting the plane light.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thedetailed description given herein below for illustration only, and thusare not limitative of the present disclosure, and wherein:

FIG. 1 illustrates an optical touch device according to the related art;

FIG. 2 a shows a method for obtaining the image of an object to bedetected and determining the position of the object by setting two imagesensors at two different positions instead of reflection element andbase plate;

FIG. 2 b shows the position and angle of the object to be detected inthe image sensed by the image sensor;

FIG. 3 a is a flowchart of a sensing method for estimating the positionof the object to be detected according to the reflective lightdistribution;

FIG. 3 b is a detailed flowchart of the step S31 in which the relativedistance between the object and the light source is estimated accordingto the reflective light distribution;

FIG. 4 a is a system block diagram of the sensing device for estimatingthe relative distance between the object to be detected and the lightsource according to the reflective light distribution;

FIG. 4 b is a system block diagram of the sensing device for estimatingthe relative distance between the object to be detected and the firstsensor unit according to the reflective light distribution;

FIG. 4 c illustrates a Universal Serial Bus (USB) using the sensingdevice according to the present disclosure;

FIGS. 5 a-5 d illustrate that the first and second sensor units in thesensing device are connected with each other by an adjusting unit;

FIGS. 6 a-6 c illustrate the conversion from touch position operation tothe cursor operation when the sensing device performs data exchange withthe host by different transmission interfaces;

FIG. 7 a shows the position variation of the object to be detected onthe real touch plane when the plane light of the light source is in thereal touch plane; and

FIG. 7 b shows the position variation of the object to be detected on astereoscopic operation plane when the plane light is on a stereoscopicoperation plane.

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the disclosed embodiments. It will be apparent,however, that one or more embodiments may be practiced without thesespecific details. In other instances, well-known structures and devicesare schematically shown in order to simplify the drawing.

The detailed characteristics and advantages of the disclosure aredescribed in the following embodiments in details, the techniques of thedisclosure can be easily understood and embodied by a person of averageskill in the art, and the related objects and advantages of thedisclosure can be easily understood by a person of average skill in theart by referring to the contents, the claims and the accompanyingdrawings disclosed in the specifications.

In order to overcome the deficiency of using the reflection element 102in the related art, the inventor provides a method for obtaining touchposition variation by using reflective light distribution in the Taiwanpatent application NO. 099117670. With reference to FIGS. 2 a and 2 b,the method will be described as below.

With reference to FIG. 2 a, FIG. 2 a shows a method for obtaining theimage of an object to be detected and determining the position of theobject by setting two image sensor modules at two different positions.This method is better than the method of related art in which reflectionelement and base plate are used.

It seems that both the method of FIG. 2 a and the method of related artuse the first image sensor module 203, the second image sensor module204, and the processing circuit 206. However, reflection element andbase plate are not needed in the method of FIG. 2 because the internalstructure of the first and second sensor units and the image obtainingprinciple differ from those of the related art.

Simply to say, the method of FIG. 2 a uses the reflection image of theobject 21 obtained from the reflective light of the object 21 instead ofthe bright area generated from a reflection element. In this method,characteristic data including the reflective light image is achieved andthe position of the object 21 can be calculated according to thecharacteristic data. The characteristic data may be the object image'sarea, length-width ratio, boundary, color, brightness, and etc.

As shown in FIG. 2 a, the first image sensor module 203 senses theposition of the object 21 along the first sensing path d1, and thesecond image sensor module 204 senses the position of the object 21along the second sensing path d2. In this situation, if the processingcircuit 206 can know the equations regarding the first and secondsensing paths d1 and d2 and thus calculate the intersection point of thetwo paths, the position of the object 21 is obtained.

FIG. 2 b shows the internal structure of the second image sensor module204 in FIG. 2 a. As shown in FIG. 2 b, the second image sensor module204 includes the image sensor 2041, the infrared ray filter 2042 (onlyinfrared ray is passed), the infrared ray transmitting unit 2043,optical lens 2044, and optical lens set 2045. The internal structure ofthe first image sensor module 203 is similar to that of the second imagesensor module 204 except that the relative distance between the infraredray transmitting unit and the optical lens of the first image sensormodule 203 and other components of the first image sensor module 203.

In this method, the first and second image sensor modules 203 and 204obtain the reflective infrared ray image of the object 21. The imagedata including the reflective infrared ray image obtained by the twosensor modules can be directly transmitted to the processing circuit 206for processing or pre-processed by the first and second image sensormodules 203 and 204 and then transmitted to the processing circuit 206.

Because the reflective infrared ray of object 21 is directly used inthis method, the deficiency of using reflection element in the relatedart can be overcome. In the other hand, the infrared ray transmittingunit is needed in the method, and thus to cut down the manufacturingcost, the present disclosure provides a method in which the number ofinfrared ray transmitting unit can be reduced.

FIG. 3 a is a flowchart of a method for sensing the position of anobject by using reflective light distribution. In particular, thesensing method includes the following steps: driving a light source togenerate a plane light (S31); forming a reflective light distribution bythe object reflecting the plane light (S33); and estimating a relativedistance between the object and the light source according to thereflective light distribution (S35).

One invention concept of the disclosure is to use a single light sourcematched with image sensor modules to achieve images including reflectivelight distribution of the object to be detected and thus calculate theposition of the object to be detected according to the images. Here, thelight source may be a point light source, and laser light,light-emitting diode (LED), and so on can be used as the point lightsource.

Preferably, a light source which can be sensed by sensor modules but notby eyes can be used in this disclosure. That is, the light source may beInfrared Ray (IR) Laser Diode (LD) or LED which emits light with wavelength greater than 780 nm. The wave length is for example 850 nm or 940nm. In this case, even if the object to be detected has differentmaterials, the reflection brightness will not be influenced.Furthermore, if the object to be detected has a dark color, thereflective light of the object may be a little dark. However, when thelight source has a high intensity, the reflective light distribution isnot much influenced because of the dark color of the object.

In the step S31, the plane light may be generated by selectively makingthe emergent ray pass through a diffractive optical element (e.g.,cylindrical lens). Alternatively, the plane light may be generated bymaking the emergent ray pass through a micro-electromechanical (MEM)mirror.

If the emergent ray from the light source passes through a diffractiveoptical element (e.g., cylindrical lens), the plane light is generateddirectly. In the other hand, if the emergent ray from the light sourcepasses through the MEM mirror, the movement and rotate speed of the MEMmirror are controlled by the MEM control system so as to convert thelight point emitted from the light source to be the plane light.

If a LED is used as the light source, the plane light may have an offsetin range of 10°-20°. In an ideal circumstance, the plane light having anoffset smaller than 5° is used in the disclosure. Therefore, if theplane light has a bigger offset, additional lens may be used to make theplane light more intensive. If a laser is used as the light source, theplane light is much ideal because the laser has a good intensity andthus additional lens is not needed.

FIG. 3 b is a detailed flowchart of the step S35 in FIG. 3 a. The stepS35 further comprises the following steps. A first image including thereflective light distribution is obtained by a sensor module (S351).Next, a first position parameter is obtained according to a plurality ofpixels corresponding to the reflective light distribution of the firstimage (S353).

In order to realize the step S353, the sensing device may be achieved byone of a sensor module and a control module, or the combination thereof.In addition, the step S353 may comprise the following steps.

Firstly, the position of center of mass of the plurality of pixels iscalculated to obtain the first position parameter (S3531). Then, therelative distance between the light source and the object to be detectedis estimated according to the first position parameter and the referencerecords which are obtained previously (S3533).

More particularly, the first position parameter in the step S3531 may beobtained by the following equation:

$( {X_{1},Y_{1}} ) = ( {\frac{\sum\limits_{i \in O_{1}}{I_{i}X_{i}}}{\sum\limits_{i \in O_{1}}I_{i}},\frac{\sum\limits_{i \in O_{1}}{I_{i}Y_{i}}}{\sum\limits_{i \in O_{1}}I_{i}}} )$

wherein, (X1, Y1) represents the first parameter. Xi, Yi represents theposition of each pixel in the digital image. Ii represents thebrightness of each pixel. That is, the first position parametercorresponding to the position of the object is calculated by using thebrightness of each pixel as weight. For example, the position of centerof mass is obtained from pixels with different brightness, and then thefirst position parameter is obtained to determine the position of theobject to be detected.

In other words, the relative distance between the object to be detectedand the light source or the sensor module may be calculated by way oflooking up tables or interpolation so long as the center, mass oraverage value of the reflective light distribution of the object fallsin the image. Suppose the resolution of the first image is 640*480pixels, the calculation result of the position of center of mass may bea decimal. Therefore, the calculated relative distance may have a higherresolution than the resolution provided by the image. For example, theresolution of the relative distance may be that of ½ sub-pixel, ¼sub-pixel, or ⅛ sub-pixel a pixel.

The reference records used in the step S3533 are information forcomparing relative distance formed by a plurality of reference positionparameters which are obtained by a setting process.

That is, the setting process is to firstly obtain the reflective lightdistributions of a reference object when the reference object is in thepreset reference positions. Here the present reference positions of thereference object are known. Then, the relation between the object andthe actual position (or distance) is obtained based on the position ofcenter of mass calculation. Finally, the actual distance between theobject and the light source or sensor module is obtained according tothe relation. The relation may be an equation regarding a relativedistance d, offset angle θ and the position of center of mass which isobtained by way of looking up tables. Alternatively, the relation may bepresented by a chart showing the relative distance d and the offsetangle θ.

Different objects in the same position may have the approximately samereflective light distribution. Therefore, pixels including reflectivelight distribution may have fixed positions in the images sensed by thesensor module. In the setting process, the reference object is moved topositions which are apart from light sources at a plurality of presetdistances. Position of center of mass calculation for the plurality ofreference reflective light distribution is performed to obtain aplurality of reference position parameters. As a result, the referencerecords may be stored in the storage unit (for example, a non-volatilememory).

That is, reference records including a plurality of reference positionparameters are provided by the setting process. The reference positionparameters refer to offset angle θ, focal length f of the lens or otherinformation when moving the reference object to the positions which areapart from the light source at a plurality of preset distances. Sincethe relative distance between the reference object and the light sourced is known, the reference position parameters may be obtained.

FIG. 4 a is a system block diagram of a sensing device for estimatingthe relative distance between the object to be detected and the lightsource according to the reflective light distribution of the object.FIG. 4 b is a system block diagram of a sensing device for estimatingthe relative distance between the object to be detected and the firstsensor unit according to the reflective light distribution of theobject.

As shown in FIGS. 4 a and 4 b, the sensing device 40 comprises the lightsource 401 and the first sensor unit 403. The first sensor unit 403 isdisposed at one side of the light source 401. For example, the firstsensor unit 403 may be disposed on the upside, downside, left side, orright side of the light source 401. Preferably, the first sensor unit403 is disposed above the light source 401. The difference between FIG.4 a and FIG. 4 b is that the former is used to estimate the relativedistance between the object 41 and the light source 401 and the latteris used to estimate the relative distance between the object 41 and thefirst sensor unit 403.

Light emitted from the light source 401 passes through the lens 402 togenerate the plane light. The first sensor unit 403 is realized by CMOSImage Sensor (CIS) or Charge Coupled Device Sensor (CCD Sensor). Thefirst sensor unit 403 estimates the relative distance d between theobject 41 and the light source 401 according to the reflective lightdistribution of the object 41. The reflective light distribution isformed by the object 41 reflecting the plane light 43.

It should be noted that the plane light generated by the light source401 is not limited to at a horizontal plane. If the plane of the planelight is parallel with the horizontal plane, the touch area may beinfinity under an ideal circumstance. If the plane light intersects thehorizontal plane to from a tangent line, the touch area may beconsidered in the plane light area, i.e., the area formed between thelens 402 and the tangent line.

Actually, in FIGS. 4 a and 4 b, the first sensor unit 403 and the lightsource 401 are only needed to be disposed at a same side of the object41. Therefore, the first sensor unit 403 can be disposed at the upside,downside, left side, or right side of the light source 401. In thepresent disclosure, the horizontal direction of the sensed imageprovides information about angle (θ), and the vertical directionprovides information of distance (R). Therefore, preferably, the firstsensor unit 403 is disposed at the upside or downside of the lightsource 401. However, if the information of distance (R) is not needed,the first sensor unit 403 may be disposed at the left side or right sideof the light source 401.

Based on the above, preferably the light source 401 is disposed at thelower portion of the sensing device 40, and the first sensor unit 403 isdisposed above the light source 401. In this case, the uniformity oflight emitted from the light source is easily controlled, and the angleand distance of the object 41 can be easily used for positioning andcursor control.

Also with reference to FIGS. 4 a and 4 b, the sensing device 40 mayfurther comprise the control unit 406, the storage unit 407, and thetransmission unit 408, each having signal connections with others.

The control unit 406 has a signal connection with the first sensor unit403. After the first sensor unit 403 senses the first image includingthe reflective light distribution, the control unit 406 may obtain thefirst position parameter corresponding to the position of the objectaccording to a plurality of pixels corresponding to the reflective lightdistribution of the first image, because the first image includes lightpoints of higher brightness which are reflected by the object to bedetected.

The storage unit 407 has a signal connection with the control unit 406so that the reference records are provided to the control unit 406. Thecontrol unit 406 calculates the position of center of mass of theplurality of pixels corresponding to the reflective light distributionof the first image, and then estimates the relative distance between theobject to be detected and the light source according to the referencerecords and the first position parameter.

The transmission unit 408 is electrically connected to the first sensorunit 403. The transmission unit 408 is used to transmit the sensed imageto a host which has a signal connection with the sensing device and toconvert the relative distance between the object and the light source tobe cursor display. The host may be computer, mobile phone, personaldigital assistant (PDA), and different types of portable electronicdevices.

FIG. 4 c shows a Universal Serial Bus (USB) using the sensing deviceaccording to the present disclosure. Based on the explanations of FIGS.4 a and 4 b, it is known that the light source 401 and the first sensorunit 403 can be set in a sensing device. In addition, the sensing deviceand the USB 408 can be formed a plug-and-play device.

Furthermore, the sensing device of the disclosure may further comprise asecond sensor unit. The operation of the second sensor unit is the sameas that of the first sensor unit. That is, the second sensor unit has asignal connection to the control unit. The second sensor unit estimatesthe relative distance between the object to be detected and the lightsource according to the reflective light distribution of the object.

FIGS. 5 a-5 d illustrate a sensing device comprising the first sensorunit 503, the second sensor unit 504, and the adjusting unit 52connecting the first and second sensor units 503 and 504. In thisembodiment, the first and second sensor units are disposed at each sideof the light source. The first image including the reflective lightdistribution is obtained by the first sensor unit, and the second imageincluding the reflective light distribution is obtained by the secondsensor unit. Then, the second position parameter is obtained accordingto a plurality of pixels corresponding to the reflective lightdistribution in the second image.

The adjusting unit 52 is disposed between the two sensor units. Theadjusting unit 52 is used to dramatically adjust the horizontal distancebetween the first sensor unit 503 and the second sensor unit 504.

The first and second sensor units 503 and 504 are disposed at each sideof the light source 501. In vertical direction, the distance between thefirst sensor unit 503 and the horizontal plane of the emergent ray canbe or not equal to the distance between the second sensor unit 504 andthe horizontal plane of the emergent ray. For simple illustration, asshown in FIGS. 5 a and 5 b, suppose the horizontal plane of the planelight is the horizontal plane of the bottom surface of the sensingdevice 50.

In FIG. 5 a, suppose that the distance h1 between the first sensor unit503 and the horizontal plane of the emergent ray is equal to thedistance h2 between the second sensor unit 504 and the horizontal planeof the emergent ray. In FIG. 5 b, suppose that the distance h1 betweenthe first sensor unit 503 and the horizontal plane of the emergent rayis not equal to the distance h2 between the second sensor unit 504 andthe horizontal plane of the emergent ray. In FIG. 5 c, the distance h3between the light source and the bottom surface of the sensing devicecan be adjusted to be equal to the distance h1 and h2, where h1 is equalto h2.

Regardless the relations between the distance h1, h2, and h3, the lengthof the adjusting unit 52 can be dramatically adjusted. That is, thehorizontal distance between the two sensor units 503 and 504 can beadjusted. When the length of the adjusting unit 52 reaches the minimumvalue, the sensing device 50 is shown in FIG. 5 d.

Based on the above, it can be concluded the following preferableembodiments.

The first preferable embodiment is shown as FIG. 4 c. In this firstembodiment, a sensor unit is used with a light source. Position of atouch point or positions of multiple touch points can be sensed by usingthe relative distance d and the offset angle θ.

The second preferable embodiment is shown as FIG. 5 a. In this secondembodiment, the first sensor unit and the second sensor unit have thesame distance to the bottom surface of the sensing device. In this case,only the offset angle θ can be obtained, but the relative distance dcannot be obtained.

The third preferable embodiment is shown as FIG. 5 b. In this thirdembodiment, the first sensor unit and the second sensor unit havedifferent distances to the bottom surface of the sensing device. In thiscase, both the offset angle θ the relative distance d can be obtained.Therefore, a virtual operation range can be defined on any plane.Furthermore, in this embodiment, the horizontal distance between the twosensor units can be adjusted, and thus embodiment can be used in a widerfield.

Whether the height of the first sensor unit is equal to that of thesecond sensor unit, or only a single sensor unit is used (as shown inFIG. 4 c), the position relations between the light source and a sensorunit can be shown as the above mentioned figures. In other words, in thepreferable embodiments as above, the position relations between thelight source and a sensor unit is provided for illustration but not as alimitation to the disclosure. Other possible position relations are notdescribed herein again.

The disclosure may estimate the relative distance between the object tobe detected and the light source according to the reflective lightdistribution at a time point. Furthermore, the disclosure may sense theposition of the object at two different time points. That is, themovement of the object can be determined. Therefore, the disclosure canbe used in the situation of continuous touch.

When determining the reflective light distribution, even if the objectis in a stereoscopic operation plane instead of a real touch plane, thesensor unit can also sense the reflective light distribution. Therefore,in the disclosure, the object can move on a real touch plane or on avirtual plane in a stereoscopic room. In other words, the area which canbe sensed by a sensor unit is defined as a sensing area. If the objectto be detected performs movement on the sensing area, variation of thereflective light distribution is generated so that the position of theobject can be determined.

To determine the touch positions at continuous time points, the methodfor determining the positions of the object comprises the followingsteps. Firstly, a first relative distance between the object and thelight source at the first time point is obtained. Secondly, a secondrelative distance between the object and the light source at the secondtime point is obtained. Thirdly, the movement of the object between thefirst time point and the second time point is determined according tothe first relative distance and the second relative distance.

Generally, the reference records may be stored and obtained by a settingprocess before leaving factory because the setting process is timeconsuming. Alternatively, the setting process can be initiated after thesensing device leaves factory. In this case, new reference records canbe dramatically sensed after a time that users begin to use the sensingdevice, in order to avoid the offset of the sensing device which iseffected by crash or other factors. Furthermore, the setting process canbe initiated before the use of the sensing device. Although this methodis time consuming, the setting process may be flexible. That is, userscan select the touch area that they would like and then perform thesetting process after adjusting the horizontal distance between thefirst sensor unit and the second sensor unit.

Even if the reference records are stored before leaving factory, thesetting process can be also provided for correction. The setting processis used to assistant the position determination during sensing flow.Therefore, that when and how to perform the setting process is notemphasized by the disclosure. The setting process is not discussedherein again.

FIGS. 6 a-6 c show conversions from the touch operation to cursoroperation where different transmission interfaces are used to transmitinformation to the host. For easy explanation, the host is a laptop.However, in actual applications, the host may be a mobile electronicdevice, a stationary electronic device, or other devices providing touchoperations.

In FIG. 6 a, the sensing device 50 is mounted in the laptop 55. That is,the sensing device 50 is disposed in the front of the keyboard of thelaptop 55. The sensing area formed between the sensor units forms atouch area having touch control function. In FIG. 6 b, the sensingdevice 50 is connected to the laptop 55 by a real port such as dongle.The distance between a first component comprising the first sensor unit503 and a second component comprising the second sensor unit 504 isadjusted by a connection component. Therefore, the size of the toucharea is flexible.

In FIGS. 6 a and 6 b, the sensing device 50 is electrically connected tothe laptop 55 by a real port. Furthermore, the sensing device 50 can beconnected to the host such as the laptop 55 or the mobile phone 56 by awired or wireless network 57, as shown in FIG. 6 c. Based on the datatransmission between the sensing device and the host, the sensed resultcan be seen on the screen of the host by for example cursor display.

The present disclosure overcomes the deficiency of the related art whichuses a reflection element to define a touch area. In this disclosure,touch operation may be performed on a virtual plane as touch area in anopen room.

It should be noted that, for easy illustration, the above embodimentsare explained under the situation that only one touch point is used at atime point. Actually, the embodiments can be implemented when more thanone touch points are used at different time points.

For dynamical touch operation, the relative distance between the touchpoint (i.e., object to be detected) and the light source/sensor unit andpositions thereof are obtained at a plurality of time points. Based onthe relative distance and positions, the movement of the object to bedetected is obtained. Furthermore, the movement of the object can beconverted to cursor operation. That is, the first relative distancebetween the object and the first sensor unit and positions thereof areobtained at the first time point by using the first sensor unit, and thesecond relative distance between the object and the second sensor unitand positions thereof are obtained at the second time point by using thesecond sensor unit. Then, the movement of the object from the first timepoint to the second time point can be obtained according to the firstrelative distance and positions and the second relative distance andpositions.

It should be noted that the positions of the object to be detected atdifferent time points are not limited to a particular touch plane. Thereflective light distribution can be also obtained even if the positionof the object is not on a real touch plane. Actually, the position ofthe object can be moved and changed in the sensing area defined by theplane light. FIGS. 7 a and 7 b illustrate the possible positions of theobject to be detected.

FIG. 7 a shows the position variation of the object on the real touchplane when the plane light of the light source is in the real touchplane. In FIG. 7 a, the plane where the object performs the touchoperation is the same as the plane where the sensing device 50 ispositioned. That is, the object to be detected is touched with a realtouch plane. The first sensor unit 503 receives the reflective lightdistribution of the object. The reflective light distribution will beused to judge the position variation of the object.

FIG. 7 b shows the position variation of the object to be detected on astereoscopic operation plane when the plane light is on a stereoscopicoperation plane. In FIG. 7 b, the plane where the object operates ishigher than the plane where the sensing device 50 is positioned. Thatis, the object does not operate on a real touch plane touching theobject but on a virtual plane in a stereoscopic room. The first sensorunit 503 receives the reflective light distribution of the object. Thereflective light distribution will be used to judge the relativeposition relation between the object and the light source 501 (or thefirst sensor unit 503).

Based on the above, the sensing method and device of the disclosuregreatly improve the usage convenience of the sensing device and enlargethe touch area. It should be noted that, in the above preferableembodiments, the storage unit stores previously the reference recordsobtained by the setting process and the reference records may be used bythe position of center of mass calculation. However, in the actualapplications, the setting process may be determined before leavingfactory or be dramatically determined before operations. In other words,the reference records can be obtained flexibly according to environment(e.g., the distance between the first sensor unit and the second sensorunit can be adjusted).

Persons skilled in the art would appreciate that various logic blocks,modules, circuits, and method steps in the above embodiments may beimplemented by electronic hardware, computer software, and thecombination there of. The connections in the implementation process,such as linking, coupling, electrical connection, or others are used toillustrate that when implementing the logic blocks, module, circuits, ormethod steps, different manners such as wired electronic signal,wireless electromagnet signal, and light signal can be used for director indirect transmission and switching of signal, data, or controlinformation. Therefore, terms in the disclosure are not understood aslimitation for implementing the connections. Other connections which arenot described in the disclosure are also within the scope of thedisclosure.

Note that the specifications relating to the above embodiments should beconstrued as exemplary rather than as limitative of the presentinvention, with many variations and modifications being readilyattainable by a person skilled in the art without departing from thespirit or scope thereof as defined by the appended claims and theirlegal equivalents.

What is claimed is:
 1. A method for sensing a position of an object,comprising: driving a light source to generate a plane light; reflectingthe plane light by the object to form a reflective light distribution;and estimating a relative distance between the object and the lightsource according to the reflective light distribution, wherein the stepof estimating the relative distance between the object and the lightsource according to the reflective light distribution comprises:obtaining a first image including the reflective light distribution; andobtaining a first position parameter according to a plurality of pixelscorresponding to the reflective light distribution of the first image,wherein the step of obtaining the first position parameter comprises:performing a calculation for a position of center of mass of theplurality of pixels corresponding to the reflective light distributionof the first image to obtain the first position parameter; andestimating the relative distance between the object and the light sourceaccording to a reference record and the first position parameter,wherein the step of performing the calculation for the position ofcenter of mass of the plurality of pixels comprises performing acalculation for the position of center of mass by using brightness ofeach pixel of the plurality of pixel as weight of each pixel, the numberof the plurality of pixels, and positions of the plurality of pixels onthe first image.
 2. The method according to claim 1, wherein the lightsource is a laser diode or a light-emitting diode (LED).
 3. The methodaccording to claim 1, wherein the light source emits an emergent ray,and the step of driving the light source to generate the plane lightcomprises: the emergent ray generating the plane light by passingthrough a cylindrical lens; or the emergent ray generating the planelight by passing through a rotatable micro-electromechanical (MEM)mirror.
 4. The method according to claim 1, wherein the referencerecords comprise a plurality of reference position parameters, and thereference position parameters are obtained by a setting process in whichthe object is disposed apart from the light source at a plurality ofpreset relative distances and the position of center of mass iscalculated for each of a plurality of reference reflective lightdistribution formed by reflecting the plane light.
 5. The methodaccording to claim 1, further comprising: obtaining a second imageincluding a reflective light distribution; and obtaining a secondposition parameter according to a plurality of pixels corresponding tothe reflective light distribution of the second image.
 6. The methodaccording to claim 5, wherein the first image and the second image areobtained respectively by a first sensor unit and a second sensor unit,and the first sensor unit and the second sensor unit are respectivelydisposed at each side of the light source.
 7. The method according toclaim 6, wherein the light source is adapted to generate a emergent rayused for forming the plane light, and distance on a vertical directionbetween the first sensor unit and a horizontal plane of the emergent rayis different from distance on the vertical direction between the secondsensor unit and the horizontal plane of the emergent ray.
 8. The methodaccording to claim 1, wherein the step of estimating the relativedistance between the object and the light source according to thereflective light distribution comprises: obtaining a first relativedistance between the object and the light source at a first time point;obtaining a second relative distance between the object and the lightsource at a second time point; and obtaining movement of the objectbetween the first time point and the second time point according to thefirst relative distance and the second relative distance.
 9. The methodaccording to claim 1, wherein the plane light defines a sensing area ona real touch plane or on a stereoscopic operation plane.
 10. A devicefor sensing a position of an object, comprising: a light source forgenerating a plane light; a first sensor unit disposed at one side ofthe light source for estimating a relative distance between the objectand the light source according to a reflective light distribution,wherein the reflective light distribution is formed by the objectreflecting the plane light; a control unit having a signal connectionwith the first sensor unit, the first sensor unit sensing a first imageincluding the reflective light distribution, and a first positionparameter being obtained according to a plurality of pixelscorresponding to the reflective light distribution of the first image;and a storage unit having a signal connection with the control unit, areference record being provided to the control unit, wherein the controlunit performs a calculation for a position of center of mass of theplurality of pixels and obtains the first position parameter, andestimates the relative distance between the object and the light sourceaccording to the reference record and the first position parameter;wherein the calculation for the position of center of mass comprisesusing brightness of each pixel as weight of each pixel, the number ofthe plurality of pixels, and positions of the plurality of pixels on thefirst image.
 11. The device according to claim 10, wherein the lightsource is a laser diode or a light-emitting diode.
 12. The deviceaccording to claim 10, wherein the light source emits an emergent ray,and the emergent ray generates the plane light by passing through acylindrical lens or a rotatable micro-electromechanical (MEM) mirror.13. The device according to claim 10, wherein the reference recordscomprises a plurality of reference position parameters, and thereference position parameters are obtained by a setting process in whichthe object is disposed apart from the light source at a plurality ofpreset relative distances and the position of center of mass iscalculated for each of a plurality of reference reflective lightdistributions formed by reflecting the plane light.
 14. The deviceaccording to claim 10, further comprising a second sensor unit having asignal connection with the control unit, wherein the second sensor unitestimating the relative distance between the object and the light sourceaccording to a reflective light distribution, wherein the reflectivelight distribution is formed by the object reflecting the plane light.15. The device according to claim 14, wherein the first sensor unit andthe second sensor unit are disposed at each side of the light source.16. The device according to claim 15, wherein the light source isadapted to generate a emergent ray used for forming the plane light, anddistance on a vertical direction between the first sensor unit and ahorizontal plane of the emergent ray is different from distance on thevertical direction between the second sensor unit and the horizontalplane of the emergent ray.
 17. The device according to claim 15, furthercomprising an adjusting unit disposed between the first sensor unit andthe second sensor unit for dynamically adjusting a horizontal distancebetween the first sensor unit and the second sensor unit.
 18. The deviceaccording to claim 10, wherein the first sensor unit obtaining a firstrelative distance between the object and the light source at a firsttime point, obtaining a second relative distance between the object andthe light source at a second time point, and obtaining movement of theobject between the first time point and the second time point accordingto the first relative distance and the second relative distance.
 19. Thedevice according to claim 10, further comprising a transmission unitelectrically connected to the sensing unit, the transmission unit beingconfigured to transmit sensed images to a host having a signalconnection to the device and to convert the relative distance betweenthe object and the light source to a cursor display.
 20. The deviceaccording to claim 10, wherein the plane light defines a sensing area ona real touch plane or on a stereoscopic operation plane.
 21. A devicefor sensing a position of an object, comprising: a light source forgenerating a plane light; a first sensor unit disposed at one side ofthe light source, for estimating a relative distance between the objectand the first sensor unit according to a reflective light distribution,wherein the reflective light distribution is formed by the objectreflecting the plane light; a control unit having a signal connectionwith the first sensor unit, wherein the first sensor unit sensing afirst image including the reflective light distribution, and a firstposition parameter being obtained according to a plurality of pixelscorresponding to the reflective light distribution of the first image; astorage unit having a signal connection with the control unit, areference record being provided to the control unit, wherein the controlunit performs a calculation for a position of center of mass of theplurality of pixels and obtains the first position parameter, andestimates the relative distance between the object and the light sourcethe first sensor unit according to the reference record and the firstposition parameter; wherein the calculation of the position of center ofmass comprises using brightness of each pixel as weight of each pixel,the number of the plurality of pixels, and positions of the plurality ofpixels on the first image.
 22. The device according to claim 21, whereinthe light source is a laser or a light-emitting diode (LED).
 23. Thedevice according to claim 21, wherein the light source emits an emergentray, and the emergent ray generates the plane light by passing through acylindrical lens or a micro-electromechanical (MEM) mirror.
 24. Thedevice according to claim 21, wherein the reference records comprises aplurality of reference position parameters, and the reference positionparameters are obtained by a setting process in which the object isdisposed apart from the first sensor unit at a plurality of presetrelative distances and the position of center of mass is calculated foreach of a plurality of reference reflective light distributions formedby reflecting the plane light.
 25. The device according to claim 21,further comprising a second sensor unit having a signal connection withthe control unit, the second sensor unit estimating the relativedistance between the object and the second sensor unit according to areflective light distribution, wherein the reflective light distributionis formed by the object reflecting the plane light.
 26. The deviceaccording to claim 25, wherein the first sensor unit and the secondsensor unit are disposed at each side of the light source.
 27. Thedevice according to claim 26, wherein the light source is adapted togenerate a emergent ray used for forming the plane light, and distanceon a vertical direction between the first sensor unit and a horizontalplane of the emergent ray is different from distance on the verticaldirection between the second sensor unit and the horizontal plane of theemergent ray.
 28. The device according to claim 26, further comprisingan adjusting unit disposed between the first sensor unit and the secondsensor unit for dramatically adjusting a horizontal distance between thefirst sensor unit and the second sensor unit.
 29. The device accordingto claim 21, wherein the first sensor unit obtaining a first relativedistance between the object and the first sensor unit at a first timepoint, obtaining a second relative distance between the object and thesecond sensor unit at a second time point, and obtaining movement of theobject between the first time point and the second time point accordingto the first relative distance and the second relative distance.
 30. Thedevice according to claim 21, further comprising a transmission unitelectrically connected to the sensing unit, the transmission unit beingconfigured to transmit sensed images to a host having a signalconnection to the device and to convert the relative distance betweenthe object and the first sensor unit to a cursor display.
 31. The deviceaccording to claim 21, wherein the plane light defines a sensing area ona real touch plane or on a stereoscopic operation plane.